Health insurance is the last thing John Oberg wants to be dealing with during what may be the final months of his mother’s life, but he can’t seem to get a straight answer about why coverage for chemotherapy at her usual hospital suddenly stopped.

His mother, Karen Oberg, 59, had been receiving treatment for her terminal stage IV lung cancer at the University of Michigan Health System, but the night before her latest appointment on Jan. 20, John Oberg says he got some bad news: the insurance company called the hospital to say it would no longer pay for his mother’s care.

“It’s absurd because my mom is literally in the middle of treatment,” John Oberg told ABCNews.com. “She’s been seeing the doctors at University of Michigan for seven months now. This is the only place she feels comfortable.”

Karen Oberg's treatment has become tangled up in bureaucratic gridlock that dozens of phone calls and a Change.org petition with 181,000 signatures have been unable to break down.

John Oberg , 26, took a leave from his job and moved back home to suburban Detroit to take care of his mother last year. He cooks and cleans for her, and never misses a doctor’s appointment. When their health insurance crisis started, he immediately got on the phone to resolve it, but the results have been frustrating, he said.

"He’s taken the bull by the horns and just charged through,” Karen Oberg said, adding that her son made 48 calls in a single day so that she can continue her outpatient care at her hospital. “I don’t have to ask him to do anything. He just steps forward.”

Karen Oberg is insured by Total Health Care through Medicaid, John Oberg said. According to University of Michigan Health System spokeswoman Nicole Fawcett, Total Health Care had been paying for Karen Oberg’s treatment despite the fact that the hospital was out of network.

“Karen’s care at U-M has been covered by Total Health Care since she first came here for a second opinion,” Fawcett told ABCNews.com in an email. “Total Health Care informed us that they would no longer continue to authorize coverage. We do not know the reason. We are currently working with them to try to restore the authorization.”

They started going to the University of Michigan hospital last spring after doctors at another hospital misdiagnosed Karen Oberg’s hip pain and told her she had some broken bones, Karen Oberg said. The University of Michigan doctors realized there were tumors on her hip, and her cancer was more advanced than once thought, she said. She's felt safest with them ever since, she said. She began her chemotherapy there in October.

John Oberg said when he reached out to Total Health Care’s chief clinical officer Linda Alexander, she insisted she never denied coverage. Nevertheless, he says she told him his mother would have to switch hospitals anyway.

At a loss, he started a petition on Change.org to persuade the insurance company to continue covering his mother at the University of Michigan Health System. More than 178,000 people signed it so far.

“I was just thrilled just watching the signatures go up,” Karen Oberg said. “It was unbelievable --still is --that there’s that many people that would take the time, the effort for me is unbelievable.”

When ABCNews.com called Alexander about the Oberg case, she said she could not go into specifics because Karen Oberg hadn’t signed a “release of information” form.

John Oberg emailed Alexander requesting the form that evening so that Alexander could speak freely, but Alexander did not respond to the request or send the form for Karen Oberg to sign.

Instead, Alexander emailed the following statement to ABCNews.com which they had also posted on the change. org website

“Total Health Care has NOT DENIED OR DELAYED TREATMENT,” it said. “Because this is a public venue, we are not able to discuss specifics regarding personal health information, as this would violate privacy rights … Our goal is to continue to deliver on our promise of being ‘Totally There’ for our members.”

"It's ridiculous that she responds like this while not even providing my mom an opportunity to sign a medical release form so that she CAN discuss it!” John Oberg wrote in an email to ABCNews.com.

Alexander later told ABCNews.com, “There is no reason why Karen’s chemotherapy cannot be continued at the University of Michigan from our perspective at Total Health Care,” but added that this is only if Karen Oberg is authorized by Total Health Care for the treatment.

John Oberg said he hasn't received a notice yet from Total Health Care authorizing his mother's care are in the University of Michigan Health System. The hospital says hasn’t received the authorization either, although it told him it has repeatedly submitted paperwork to the insurance for that authorization, he said.

John Oberg said he plans to file a complaint with the Michigan Department of Insurance and Financial Services.

“Something is not being communicated effectively here,” said Renee Campbell, a manager of the insurance unit of that department, who learned of the Obergs' case from ABCNews.com.

Campbell said the Obergs have a few options for dealing with the coverage dispute, and her office regularly facilitates communication between insurance providers, patients and hospitals.

Patients can appeal insurance coverage decisions, and many states have offices set up to help patients facilitate these conversations with their insurers and providers, said Cheryl Fish-Parcham, the deputy director of health policy at Families USA, a national consumer protection nonprofit.

Since Karen Oberg has Total Health Care through Medicaid, she actually has two options in Michigan, Campbell, a manager of the insurance unit with the state’s office of consumer services: she can file an appeal through the state’s Medicaid ombudsman or through her unit within the Department of Insurance and Financial Services. There’s even a special form to expedite the process if the person needs covered care urgently, she said.

“This is something that our office deals with on a daily basis with consumers,” Campbell said. “Sometimes, just putting something in writing and getting it to our office is sometimes enough to get things moving.”